Apparatus for roll pressure bonding

ABSTRACT

The application describes a method and apparatus for roll pressure bonding a plurality of stripes to a substrate. Through unique roll arrangements and designs, stripes of controllable thickness are produced, as conditions which cause non-uniform roll pressures are eliminated. Furthermore, these unique roll arrangements and designs protect the substrate in the areas between the stripes from surface damage such as roll scratching. Additionally, novel means are provided which both guide and heat the materials.

United States Patent 91 Kozak et a1.

[54] APPARATUS FOR ROLL PRESSURE BONDING [75] Inventors: Larry M. Kozak,Tarentum;

Raymond L. Southern, Lower Burrell, both of Pa.

[73] Assignee: Allegheny Ludlum Industries, Inc.,

Pittsburgh, Pa.

[22] Filed: June 11, 1971 [21] AppL No.: 152,318

Related US. Application Data [62] Division of Ser. No. 824,205, May 13,1969, Pat. No.

[52] U.S. Cl. ..228/4, 29/47l.1, 29/4975, 156/178, 156/302, 228/5,228/44 [51] Int. Cl. ..B23k 1/00 [58] Field of Search .228/4, 5, 6, 44;219/470; 72/236; 29/471.l, 471.3, 497.5,

[5 6] References Cited UNITED STATES PATENTS 3,424,362 1/1969 Morey..228/5 1 May 22, 1973 3,423,573 1/1969 Richards et a1 219/470 X3,201,862 8/1965 Gotoh ..29/47 1 .1 3,195,332 7/1965 Ranauto .....72/236X 2,980,159 4/1961 Greene........ 156/554 X 2,782,497 2/1957 Campbell29/4975 X 2,722,735 11/1955 Beamish t ..228/5 X 2,414,511 1/1947 Dyar..228/5 X Primary ExaminerJ. Spencer Overholser Assistant ExaminerRobertJ. Craig Att0rney- Richard A. Speer and Vincent G. Gioia [57] ABSTRACTThe application describes a method and apparatus for roll pressurebonding a plurality of stripes to a substrate. Through unique rollarrangements and designs, stripes of controllable thickness areproduced, as conditions which cause non-uniform roll pressures areeliminated. Furthermore, these unique roll arrangements and designsprotect the substrate in the areas between the stripes from surfacedamage such as roll scratching. Additionally, novel means are providedwhich both guide and heat the materials.

10 Claims, 8 Drawing Figures Patented May 22, 1973 3,734,384

4 Sheets-$heet 1 F/G. c 2 Z0 INVEN TORS. RAYMOND L. SOUTHERN 8 LARRY M.KOZAK \LJ A M A! Iorney Patented May 22, 1973 3,734,384

4 Sheets-Sheet 2 FIG. 3. 2/

2:; 22 26 24 25 g {I Q 25 /a /9 l 18 nv VEN r023. RAYMOND L. SOUTHERN aLARRY M. KOZAK VWhUK/S- A Attorney Patented May 22, 1973 4 Sheets-Sheet5 INVENTORS. RA YMO/VD L. SOUTHERN 8 LARRY M. KOZAK A! rorney PatentedMay 22, 1973 3,734,384

4 Sheecs5heet 4 IN VEN TORS. RAYMOND L. SOUTHERN 8 LARRY M. KOZAK VM/ilAttorney APPARATUS FOR ROLL PRESSURE BONDING This application is adivision of U.S. application Ser. No. 824,205 filed May 13, 1969, nowU.S. Pat. No. 3,632,034 issued Jan. 4, 1972.

This application relates to a method and apparatus for pressure bondinga first material to a second material and more particularly to a methodand apparatus for pressure bonding a plurality of spaced apart stripesto a substrate.

Roll bonding of composite members is widely accepted today. Cookware isoften made from composite aluminum-stainless steel stock. Aluminumoffers excellent heat transfer characteristics but is susceptible tostaining and difficult to clean. On the other hand stainless steel doesnot have the heat transfer characteristics of aluminum but can easily becleaned and is resistant to stain. Titanium-aluminum composites are alsomade since they provide a stock material which has an outer surface oftitanium with its inherent strength and corrosion resistance and a coreof less expensive aluminum. More recently, stainless steel substrateshave been pressure bonded to metal more anodic than carbon steel so asto produce composite stock suitable for fabrication into automotive andother decorative trim members.

Stainless steel is ideally suited for automotive trim as it has a brightlustrous surface and is stain resistant to a variety of contaminants.However, since most automotive bodies are constructed of carbon steel,the use of stainless steel can result in galvanic corrosion. Carbonsteel is anodic to stainless steel and galvanically corrodes in thevicinity of the stainless steel trim in the presence of an electrolyte,such as moisture.

To protect the carbon steel it has been the practice to coat stainlesssteel with a non-ferrous sacrificial metal which is electrochemicallyanodic to mild carbon steel prior to forming the stainless into trimmembers. The sacrificial metal is applied to those sections which willeventually contact the automotive body, i.e. the return flange of thefabricated trim members. This generally encompasses the bonding ofsacrificial metal to the upper planar surfaces of stainless substratesalong their edges and at regular intervals thereacross, therebyproducing stripes of sacrificial metal at each edge and across thesurface. The stripes across the surfaces are twice the width of the edgestripes and are -slit along their longitudinal axis so as to producestrips of stainless steel of a desired width with sacrificial stripes ateach edge, suitable for fabrication into automotive trim members.

The presently preferred method for coating the stainless substrate isroll pressure bonding. Although roll bonding equipment has been used inthe past for producing composite members, e.g. cookware: a roll bonderwhich could satisfactorily bond a plurality of uniformly thick spacedapart stripes to a substrate had not existed until the presentinvention. Conventional roll bonders comprise an upper work roll and alower work roll. They are subject to barrelling, a condition caused byheat concentration gradients within the roll and/r deflectionconcavity", a condition caused by pressure differentials.

Heated sheets passing through a roll transfer heat to the roll.Unfortunately the heat is not uniformly distributed throughout the rolland concentrates in the center. As a result the center of the rollexpands to a greater degree than does the ends, thereby assuming theshape LII of a barrel; a shape adverse to quality bonding as it 'causesthe central material, e.g. center stripes of sacrificial metal, to beover rolled and compressed to a greater extent than the end material, egedge stripes of sacrificial metal. Like barreling the phenomenon ofdeflection concavity is also disadvantageous. It is caused by unevenpressure loads which cause the roll surface to be concave in the bondingzone. Over rolling of the end material is characteristic of it.

Our invention teaches a method and apparatus for producing roll bondedstripes of controllable thickness by providing controllable pressure tothe widths of material which form the stripes after bonding. We havethree preferred embodiments for carrying out the invention, all of whichsubstantially eliminate the adverse effects of barreling. They comprise:(1) a flexible work roll with a plurality of spaced apart backup rolls:(2) a relieved ring work roll; and (3) a plurality of work rolls. Inaddition to the substantial elimination of barreling the first and thirdembodiments substantially eliminate the adverse effects of deflectionconcavity. All the embodiments have the advantage of substantiallyeliminating the problem of scratching substrate metal in the areabetween bonded stripes. This is very important as this area becomes theexposure surface of stainless steel automotive trim members. A furtherfeature of this invention is a novel means which performs the dualfunctions of guiding and heating the materials which form the compositestock.

It is accordingly an object of this invention to provide novel apparatusfor roll pressure bonding.

It is another object of this invention to provide a novel method forroll pressure bonding.

It is another object of this invention to provide a novel apparatus foruniformly roll pressure bonding a plurality of spaced apart stripes to asubstrate.

It is another object of this invention to provide a novel method foruniformly roll pressure bonding a plurality of spaced apart stripes to asubstrate.

It is another object of this invention to provide novel means for bothheating and guiding material to be hot rolled pressed.

It is a further object of this invention to provide a novel method forboth heating and guiding material to be hot rolled pressed.

The foregoing and other objects of the invention will be best understoodfrom thefollowing description, reference being had to the accompanyingdrawings wherein:

FIG. 1 is a schematic side view of one possible arrangement for theapparatus of this invention;

FIG. 2 is a partial end elevational view-looking at the rolls where thebonded material exitstherefrom, a portion of which is sectional, showingone of the roll pressure bonding embodiments of this invention;

FIG. 3 is a partial side elevational view taken substantially along lineIIIIII of FIG. 2, a portion of which is sectional, showing the rollarrangement embodiment of FIG. 2;

FIG. 4 is a side view of the lifter spring mechanism for the work rollof the roll arrangement embodiment of FIGS. 2 and 3;

FIG. 5 is an end view of the bracket which holds the lifter springmechanism of FIG. 4;

FIG. 6 is a partial end elevational view looking at the rolls where thebonded material exitsitherefrom, showing a second roll pressure bondingembodiment of this invention;

FIG. 7 is a partial end elevational view looking at the rolls where thebonded material exits therefrom, showing a third roll pressure bondingembodiment of this invention;

FIG. 8 is a sectional view of a means for both heating and guidingmaterial.

We refer now to the drawings for a description of the apparatus andmethod of this invention. Since a primary use for the invention is themanufacture of sacrificial coated stainless steel automotive trim, thefollowing discussions and examples are directed to this embodiment. Aspointed out earlier, the sacrificial metal is one which is anodic tomild carbon steel. Typical sacrificial metals are aluminum, zinc,cadmium, magnesium and base alloys and mixtures thereof. They can besupplied in a variety of widths in the form of wire, sheet, foil orpowder. At the present time aluminum wire is preferred.

FIG. 1 is a schematic side view of one possible arrangement for theapparatus of this invention. It comprises a coil 1 of stainless steel,adapted to be supplied from any conventional uncoiler, a plurality ofspools 2 of aluminum wire (only one of which is shown), also adapted tobe supplied by suitable uncoiling means, a first guide means 3 and asecond guide means 4 for the an embodiment of roll stand 10, a portionof which is in section. It comprises roll stand frame 20, upper workroll 11, lower work roll 12, a plurality of backup rolls 13 seated inhousings 23, an upper work roll shaft 14 seated in thrust bearings 15(FIG. 5), chocks l6 enclosing thrust bearings 15, brackets connectingchocks 16 to the roll stand frame 20 through work roll lifter springs17, and pressure cylinders 18 for raising and lowering backup rollers 13through plungers 19, backup roll movers 21, rocker arms 22 andadditional parts shown in FIG. 3 and described below. Upper work roll11' is flexible and is straddled by a plurality of backup rolls 13 (seeFIG. 3 which shows the strad dling) spaced apart so as to distributeuniform pressure to the metal which forms the sacrificial stripes. It issmall enough so that it will bend rather than over-roll any section. Forthe production of aluminum coated stainless steel automotive trim, theflexible upper work roll is generally no greater than 3" providing it issolid. Hollow flexible rolls can be larger. Their sectional moment ofinertia, however, should be no greater than that for the largest useablesolid roll. Rolls larger than 3 inches could be employed to bond metalwires harder wire, radiant heaters 5 for bringing the stainless todesired temperature, a strip guide 6 for the stainless steel, a sprayhead 7 and a rolling stand 10. Rolling stand 10 comprises a top'workroll 11 and a bottom work roll 12 which are designed and arranged in amanner so as to bond a plurality of controllably thick aluminum stripesto the stainless. The details of the arrangements and designs arediscussed below. Guide rolls and means 3, 4 and 6 are arranged in apurely exemplary manner which should in no way be construed as limiting.For example, they can be replaced by suitable supplying means whichserve the dual functions of supplying and guiding. The radiant heaters 5are also exemplary and can be replaced by other well-known conventionalheating means, e.g. induction furnaces and resistance heating means.Furthermore, there are instances when a cold pressure bond is desiredand hence no need for heating means. Heating of the sacrificial aluminumwire does not require heating means even when hot roll bonds are formed,as it can be heated by conduction, i.e., by bringing it into contactwith the heated stainless steel, since the aluminum is of a relativelysmall mass in comparison to the stainless. An alternative heating methodfor the aluminum is a heated guide roll, shown in FIG. 8 and describedbelow. Spray head 7 issues a release agent, e.g. a fine mist of watermixed with lubricants or minerals, through air atomizing nozzles. Thepurpose of spraying is to prevent the wire from being seized by theupper work roll and not for lubricity or cooling. The impurities in thewater, e.g. oil or silicone, deposit a very thin film on the surface ofthe roll as the water evaporates. This surface film fills in the surfacepits of the roll and prevents the aluminum from getting caught in them.Of course, spraying can be replaced by other means for applying releaseagents, e.g. brushes and rolls. It is also possible to apply the releaseagent by hand, e.g. rubbing.

A preferred roll arrangement and design for producing uniform stripes ofsacrificial metal is shown in FIGS 2 through 5. FIG. 2 is a partial endelevational view of than aluminum.

FIG. 3 is a partial side elevational view, a portion of which is insection, of the roll stand embodiment of FIG. 2, showing one particularmeans for raising and lowering the backup rolis 13. It compriseshydraulic pressures cylinders 18 connected to rocker arms 24 throughpivots 25 about which rocker arms 24 turn, pivots 26 also about whichrocker arms 24 turn, a backup roller mover 21 which raises and lowersplunger 19 through rocker arm 22, and a housing 23 which holds backuprollers 13 and moves with connected plunger 19. When pressure cylinders18 push upward, rocker arms 24 revolve, thereby lowering plungers 19 andbackup rolls 13. Conversely, when pressure cylinders 18 push down,rocker arms 24 revolve in the opposite directions, thereby raisingplungers 19 and backup rolls 13. Although the exemplary means describedin this paragraph for raising and lowering the backup rolls 13 show aset of straddle rolls in the same horizontal plane, it is within thescope of this invention to use sets of offset straddled backup rolls,e.g. every other backup roll could be removed alternately side to side,to use a plurality of sets of straddled rolls having in excess of tworolls each and to replace the plurality of sets of straddled backuprolls with a plurality of non-straddling backup rolls.

When backup rolls 13 are raised work roll 11 is also raised. This isaccomplished by work roll lifter springs 17 and brackets 25 which areattached to roll stand frame 20. The operation of lifter springs 17 isbest described in conjunction with FIGS. 4 and 5. FIG. 4 shows a sideview of the lifter spring mechanism and FIG. 5 shows an end view of thebracket which holds the lifter spring mechanism. Comprising FIG. 4 arelifter spring 17 connected to bracket 25 at one end and to chock 16 atthe other end and track 27 cut from bracket 25 upon which chock 16slides up and down. FIG. 5 comprises bracket 25, chock 16, thrustbearing 15 within chock 16 and upper work roll shaft 14 within thrustbearing 15. When the backup rolls 13 relieve the pressure upon the upperwork roll 11', it is pulled up by chocks 16 which are in turn pulled upby work roll lifter springs 17 while chocks 16 slide on tracks 27. Likethe apparatus for raising and lowering the backup rolls the apparatusfor raising the upper work roll as described in this paragraph and asshown in FIGS. 4 and 5 is only exemplary and should in no way beconstrued as limiting.

Placing the apparatus as shown in FIGS. 1 through 5 into operation is asfollows. Spools of aluminum wire are placed in position as is a coil ofstainless steel. The aluminum wires are then threaded over the firstguide 3, under the second guide 4, and between upper work roll 11 andlower work roll 12'. Upper work roll 11' is in its raised position heldby chocks 16 which are in turn held by lifter springs 17. At the sametime the stainless steel is passed through unenergized radiant heaters5, strip guide 6 and between upper work roll 11' and lower work roll12'. The aluminum wires and stainless steel are then placed on a coiler(not shown). Subsequently, backup rolls 13 are lowered as describedearlier, thereby also lowering upper work roll 11 so as to arrange itand lower work roll 12' in their bonding position. Radiant heaters 5 arenext energized to heat the stainless steel to a preferred bondingtemperature, i.e., a temperature of at least 375F. The aluminum israised to a preferred bonding temperature, i.e., a temperature of atleast 140F, by heat transferred from the stainless steel as it isbrought into contact with the heated stainless steel prior to entry intothe nip of the rolls. Power is then supplied to drive the coiler whichacts as the driving force withdrawing stainless steel sheets through theroll with spaced apart uniform stripes of aluminum bonded thereto. As analternative, one or more work rolls may be driven instead of the coiler.

A second embodiment of this invention eliminates barreling through aplurality of upper work rolls and both barreling and deflectionconcavity through a plurality of upper work rolls, each having their ownpressure supplying means. FIG. 6 shows an example of this embodiment. Itcomprises a plurality of upper work rolls 11'', a plurality of hydraulicpressure cylinders 30 connected to the upper work rolls 11 through aplurality of housings 38, a plurality of saddles 31 connected to thehydraulic cylinders 30, an arbor 32 seated within saddles 31 holding theupper work rolls 11" in place against a lower work roll 12" through thesaddles 31, hydraulic pressure cylinders 30 and housings 38, invertedworm gear screw jacks 33 for raising and lowering the arbor 32 and ahand wheel 36 connected to the jacks through shafts 34 couplings 35 andshaft 37. As was the case for the first embodiment, modifications andchanges of the structure shown in FIG. 6 are well within the scope ofthis invention. For example, the plurality of hydraulic cylinders couldbe replaced by a plurality of springs or weights or eliminated entirely.

FIG. 7 shows a third embodiment of this invention. It comprises arelieved ring upper work roll 11" and a lower work roll 12". Relievedring roll 11" comprises rings 40 arranged so as to conform to the wiresbeing bonded, spacers 41 and locking collars 42 to hold the rings inwires. through set screws (not shown). This embodiment workssatisfactorily with the bottom roll as is shown in FIG. 7 but it hasbeen found preferable to use two relieved ring rolls. When two relievedring rolls are used the rings on the bottom roll are generally widerthan those on the top as they do not have to conform to the wires. Thisthird embodiment can be made operable by removing the plurality of upperwork rolls, the hydraulic pressure cylinders and the saddles shown inFIG. 6 and by replacing the arbor with the ring relieved roll shown inFIG. 7. It is an additionally advantageous embodiment as is the secondembodiment since it is adaptable to a bonding process wherein thealuminum is embedded into the stainless. This advantage is made possibleby the high concentration of pressure obtainable at the bonding surfaceof the ring.

Earlier it was disclosed that one of the objects of this invention wasto provide a novel method and apparatus for heating the material to bebonded. This is accomplished by a guide means which performs the dualfunctions of guiding and heating. FIG. 8 shows such a guide means in theform of a roll suitable for guiding wires This concept is, however,adaptable to sliding guide means and guide means suitable for otherforms of material, e.g. foil. The guide means as shown in FIG. 8comprises a stationary journal tube 50 surrounding a heating element 51,self-lubricating bearings 52 and wire guide groove blocks 53 surroundingjournal tube 50 and locking collars 54 for holding self-lubricatingbearings 52 and guide groove blocks 53 in place by means of set screws55.

From the above paragraphs it will be apparent to those skilled in theart that the novel principles of the invention disclosed herein inconnection with specific examples thereof will suggest various othermodifications and applications of the same. It is accordingly desiredthat in construing the breadth of the appended claims they should not belimited to the specific examples described herein.

We claim:

1. Apparatus for roll pressure bonding a plurality of spaced apartstripes to a substrate including in combination means for supplying aplurality of spaced apart widths of striping material; means forsupplying a substrate; roll pressure bonding means for applyingsubstantially uniform pressure to each width of striping during bonding,said bonding means comprising} a lower work roll which contacts saidsubstrate, a plurality of individually adjustable upper work rollsaligned to contact said plurality of spaced apart widths of stripingmaterial, said plurality of upper work rolls being spaced apart atdistances corresponding at most to the respective distances between thespaced apart widths of striping material to which they are aligned;means for guiding said plurality of spaced apart widths of stripingmaterial to said roll pressure bonding means; and means for receivingsaid substrate from said roll pressure bonding means with said pluralityof spaced apart stripes bonded thereto.

2. Apparatus according to claim 1 including means for heating saidsubstrate.

3. Apparatus according to claim 1 including means for heating saidplurality of spaced apart widthsgof striping material. 5

4. Apparatus according to claim 1 including heating guide means forheating and guiding said plurality of spaced apart widths of stripingmaterial.

5. Apparatus according to claim 4'wherein said heating guide meanscomprises a heated guide roll.

6. Apparatus according to claim 1 including means for applying a releaseagent to said roll pressure bonding means.

7. Apparatus according to claim 1 including means for withdrawing saidplurality of spaced apart widths of striping material and said substratefrom their respec- 10. Apparatus according to claim 1 including aplurality of pressure applying means, each of which is connected to oneof said upper work rolls to adjust the pressure of each of said upperwork rolls against said lower work roll.

1. Apparatus for roll pressure bonding a plurality of spaced apartstripes to a substrate including in combination means for supplying aplurality of spaced apart widths of striping material; means forsupplying a substrate; roll pressure bonding means for applyingsubstantially uniform pressure to each width of striping during bonding,said bonding means comprising a lower work roll which contacts saidsubstrate, a plurality of individually adjustable upper work rollsaligned to contact said plurality of spaced apart widths of stripingmaterial, said plurality of upper work rolls being spaced apart atdistances corresponding at most to the respective distances between thespaced apart widths of striping material to which they are aligned;means for guiding said plurality of spaced apart widths of stripingmaterial to said roll pressure bonding means; and means for receivingsaid substrate from said roll pressure bonding means with said pluralityof spaced apart stripes bonded thereto.
 2. Apparatus according to claim1 including means for heating said substrate.
 3. Apparatus according toclaim 1 including means for heating said plurality of spaced apartwidths of striping material.
 4. Apparatus according to claim 1 includingheating guide means for heating and guiding said plurality of spacedapart widths of striping material.
 5. Apparatus according to claim 4wherein said heating guide means comprises a heated guide roll. 6.Apparatus according to claim 1 including means for applying a releaseagent to said roll pressure bonding means.
 7. Apparatus according toclaim 1 including means for withdrawing said plurality of spaced apartwidths of striping material and said substrate from their respectivesupplying means through said roll pressure bonding means.
 8. Apparatusaccording to claim 7 wherein said receiving means and said withdrawingmeans comprises a power driven coiler.
 9. Apparatus according to claim 7wherein said withdrawing means comprises a power driven work roll. 10.Apparatus according to claim 1 including a plurality of pressureapplying means, each of which is connected to one of said upper workrolls to adjust the pressure of each of said upper work rolls againstsaid lower work roll.